WO2000040174A1 - Device for treating presbyopia or other ocular disorder - Google Patents

Abstract

The invention concerns a device for treating presbyopia or other ocular disorders related to an eye accommodation defect. Said device (20) comprises a piece (22) having substantially the shape of at least a ring portion with an axis of revolution and first (22a) and second (22b) edges offset along radial directions and along the direction of said axis of revolution, said first edge (22a) being designed to rest, over at least part of its length, on part of the eye internal wall and said second part (22b) capable of being pressed against a median zone (18c) of zonules of the crystalline lens (18), whereby is obtained a displacement of the median zone of said zonules stressing them and enabling them to cause the deformation of the crystalline lens (14) under the effects of stimulation applied to said zonules.

Description

1. Device for treating presbyopia or other eye conditions linked to a defect in accommodation of the eye, characterized in that it comprises a part (22) having substantially the shape of at least one portion of a ring having a axis of revolution and a first edge (22a) disposed on a circle of diameter Dl between 12.5 and 13.5 mm and a second edge (22b) disposed on a circle of diameter D2 between 9.5 and 10.5 mm, said edges being offset in the direction of said axis of revolution by a length h of between 0.5 and 2.5 mm. said first edge (22a) being intended to be supported, by at least part of its length, on a part of the inner wall of the eye and said second edge (22b) being able to be applied against a median zone ( 18c) of the zonules (18) of the lens, whereby a displacement is obtained of said median zone of said zonules causing them to be tensioned and making them capable of causing deformation of the lens (14) under the effect of stimulations applied to said zonules .

2. Device according to claim 1, characterized in that the offset along the axis of revolution, between the first edge (22a) and the second edge (22b) is between 1.0 mm and 1.5 mm.

3. Device according to any one of claims 1 and 2, characterized in that said first edge (22a) is constituted by circular arcs (26) separated by recessed portions (28).

4. Device according to claim 3, characterized in that said circular arcs (26) forming said first edge (22a) are angularly regularly distributed with respect to said axis of revolution.

5. Device according to any one of claims 1 to 4, characterized in that said part (22) has the shape of an open ring terminated by two ends (30, 32). 6. Device according to any one of claims 1 to 4, characterized in that said part (22) has the shape of a closed ring.

7. Device according to any one of claims 1 to 4, characterized in that said part (22) has the shape of a ring portion terminated by two ends (30, 32). the angle at the center between these ends being between 30 and 120 degrees. 8. Device according to claim 7, characterized in that one (30) of the two ends (30, 32) of the part (22) in the form of a ring portion is extended by a tapered portion (35) in order to facilitate the placement of the ring in the eye. 9. Device according to any one of claims 7 and 8, characterized in that it is made of a rigid biocompatible material.

10. Device according to claim 9, characterized in that it is made of PMMA.

11. Device according to any one of claims 1 to 8, characterized in that it is made of a flexible biocompatible material.

12. Device according to any one of claims 1 to 1 1, characterized in that the edges (22a. 22b) of said ring are rounded.

13. Device according to any one of claims 1 to 12, characterized in that the ring (22) has the shape of a portion of truncated cone.

Device for treating presbyopia or other eye condition

The present invention relates to a device intended to be put in place in the eye to treat presbyopia or other ocular conditions linked to a defect in accommodation of the eye.

In order to better understand the problem to be solved, there is shown in attached FIG. 1 a half-view in vertical section of an eye. This figure shows the cornea 2, the inner wall of the eye 4 with its ciliary body 6 and the iris 8 which defines the pupil 9 of the eye. This figure also shows the sulcus which constitutes a groove between the ciliary body 6 and the iris 8 as well as the lens 14 with its capsular bag 16. The lens 14 or, more precisely, its capsular bag 16 is connected to the wall 4 of the eye by a set of muscles called zonules 18 constituted by fibrils. These fibrils have one end 18a which is connected to the periphery of the capsular bag 16 and another end which is embedded in the ciliary body 6. When the eye is in a normal state, the controlled contractions of the zonules 18 cause the modification of the rays of curvature of the lens 14 thus allowing accommodation of the eye as a function of the distance at which the object to be looked at is located.

It has been demonstrated that the aging of the eye tends to produce an increase in the outside diameter of the lens. As a result, the zonules become "too long" and are "relaxed" and that the impulses applied to the fibrils of the zonules no longer allow them to act on the lens to cause accommodation.

It has also been demonstrated that it is the traction exerted on the capsular bag by the zonules which makes it possible to increase the optical power of the lens by causing a reduction in the radius of curvature of its posterior face.

An object of the present invention is to provide an implantable device in the eye which makes it possible to make the zonules active again to allow accommodation despite the increase in the diameter of the lens.

To achieve this object, according to the invention, the device for treating presbyopia or other eye condition linked to a defect in accommodation of the eye is characterized in that it comprises a part having substantially the shape of at least one portion of ring having an axis of revolution and a first edge disposed on a circle of diameter D1 between 12.5 and 13.5 mm and a second edge disposed on a circle of diameter D2 between 9.5 and 10.5 mm, said edges being offset in the direction of said axis of revolution with a length h of between 0.5 and 2.5 mm, said first edge being intended to be supported, by at least part of its length, on part of the wall internal of the eye and said second edge being able to be applied against a median zone of the zonules of the lens, whereby a displacement is obtained of said median zone of said zonules causing their tensioning and making them capable of causing deformation of the lens under the effect of stimulations applied to said zonules. It is understood that the ring or the portion of ring placed inside the eye is supported by its outer edge in the area of the ciliary sulcus while its other inner edge applied against the middle area of the zonules causes the backward displacement of this median zone of the zonules as well as of the lens. This displacement makes it possible to obtain a new tension of the zonules which will thus be made active again when the fibrils which constitute them are excited. According to a first embodiment of the invention, the ring is closed and it is then made of a flexible biocompatible material in order to allow the insertion of the ring inside the eye. According to a second embodiment of the invention, the ring is open and it can, in this case, be made of a rigid biocompatible material such as for example PMMA. In the present text, it should be specified that by "flexible material" is meant materials commonly used to manufacture in particular intraocular implants and which are typically constituted by polyHEMA or by silicone gels. By the term "rigid material" is meant biocompatible translucent materials having a low coefficient of elasticity and the best known representative of which is PMMA.

Other characteristics and advantages of the invention will appear better on reading the following description of embodiments of the invention given by way of nonlimiting examples. The description refers to the appended figures, in which: - Figure 1 already described shows half of an eye in vertical section;

- Figure 2 shows the establishment in the eye of the treatment device for presbyopia;

- Figure 3 is a diagram illustrating the mode of action of the device for the treatment of presbyopia; - Figure 4 is a front view of an embodiment of the device for the treatment of presbyopia; - Figure 5 is a side view in section along the line VV of the device of Figure 4; and

- Figure 5a is a partial sectional view of the line A-A of Figure 4. Referring first to Figures 4 and 5, we will describe an embodiment of the device for treating presbyopia. This device referenced 20 has the general shape of a ring or a portion of a ring 22 comprising an outer edge 22a and an inner edge 22b. The ring 22 can be closed or have an opening as it appears in FIG. 4. The edges 22a and 22b can have a rounded shape and are interconnected by a flat portion 22c.

In Figure 2, there is shown a processing device 20 placed in the eye. As this figure shows, the outer edge 22a is in contact with the wall of the eye in the area of the ciliary sulcus 10 while the inner edge 22b is applied against the middle area 18 of the zonules 18c so as to cause the displacement of this middle zone as will be explained later.

The intermediate zone 22c of the ring or of the ring portion 22 must have sufficient dimensions for the internal edge 22b to effectively allow the displacement of the middle zone of the zonules. That is to say that the intermediate part 22c must have sufficient mechanical strength so that the distance between the external and internal edges remains constant when the ring is put in place. These dimensions will of course depend on the material used to obtain the desired mechanical strength. As shown in FIG. 2 or FIG. 5a, the ring 22 has the general shape of a portion of a truncated cone so that the outer edge 22a is placed on a circle of diameter D 1 so that the inner edge 22b is disposed on a circle of diameter D2 less than Dl and that an offset h in the direction of the optical axis XX 'exists between the outer edge 22a and the inner edge 22b.

When the treatment device is placed in the eye, the edge 22a constitutes an anterior edge and the edge 22b a posterior edge. In Figure 3, there is shown schematically the effect produced by the establishment of the treatment device 20 in the eye. In this figure, we have symbolized by B a fictitious anchor point of the zonules in the ciliary body and by Al the anchor point of the zonules on the periphery of the capsular bag, 13 representing the distance between points B and Al in l absence of the treatment device. By the action of the internal edge 22b on the median zone of the zonules, the fibrils constituting the zonules see their median part C displaced by distance d towards the back of the eye. This displacement of the middle zone C also causes a displacement of the point Al which is then called A ']. The displacement along the direction of the optical axis is equal to d and a displacement is also obtained in directions orthogonal to the optical axis, that is to say along the radial directions of the lens, of value e. It is understood that these anteroposterior displacements cause a certain displacement towards the rear of the whole of the lens and allow a tensioning of the zonules thanks to the displacement of the median zone. Everything happens, with respect to the lens, as if the length of the zonules had been reduced by the length e. This compensates for the increase in the diameter of the lens.

Referring again to FIGS. 4 and 5, a preferred embodiment of the treatment device 20 will be described in more detail. The central part of the ring 20 referenced 22c is preferably pierced with orifices 24 angularly regularly spaced apart and allowing the free circulation of the aqueous humor on either side of the device in the anterior chamber. Likewise, the outer edge 22a is preferably constituted by arcs of a circle such as 26 separated by recessed regions 28. The arcs of a circle 26 are angularly regularly distributed. Consequently, the support on the inner wall of the eye is produced by the only sectors corresponding to the arcs of a circle 26, the recessed portions 28 also allowing the free passage of the aqueous humor.

In the case of the embodiment of FIG. 4, the treatment device 22 is simply constituted by a portion of ring limited by ends 30 and 32 leaving an opening 34. Preferably, to facilitate the insertion of the ring in the eye through the incision made in the wall thereof, the end 30 can be provided with a tapered extension 34.

In the case where the treatment device 20 consists of only a portion of ring having the opening 34, it is possible to produce this ring from a rigid material such as PMMA. The opening 34 may preferably be between 30 and 120 degrees, thus ensuring sufficient action on the zonules.

It is also possible to use a treatment device constituted by a closed ring and therefore devoid of the opening 34. In this case of course, it is necessary that this ring is made of a flexible material of the type sold under the brand Hydrogel to allow the folding of the ring around a diameter for the introduction of the device 20 into the eye through an incision of relatively small size. In the embodiment described by way of example, the external diameter D1 is equal to 13.1 mm and the internal diameter D2 is equal to 9.9 mm. More generally, the diameter D1 is preferably between 12.5 and 13.5 mm and the diameter D2 between 9.5 and 10.5 mm. The offset h between the two edges in the direction of the optical axis is equal to 1.25 mm in order to obtain sufficient displacement of the median zone of the zonules. More generally, this offset h is between 0.5 and 2.5 mm and preferably between 1 and 1.5 mm.

The opening angle 34 between the two ends of the ring is 35 degrees. More generally, it is between 30 and 120 degrees.

Finally preferably, as shown in Figures 5 and 5a, the outer and inner edges respectively of the ring 20 have a rounded shape. The corresponding radius of curvature is preferably between 0.20 and 0.35 mm in order to avoid any damage to the zonules or to the internal wall of the eye.